Fluid-attenuated inversion recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF) effects on the image, so as to bring out the periventricular hyperintense lesions, such as multiple sclerosis (MS) plaques.[1] It was invented by Graeme Bydder.[citation needed] FLAIR can be used with both three-dimensional imaging (3D FLAIR) or two dimensional imaging (2D FLAIR).
Postcontrast FLAIR of a case of meningitis. It shows enhancement of meninges at the tentorium and in the parietal region, with evidence of dilated ventricles.
By carefully choosing the inversion time (TI), the signal from any particular tissue can be nulled. The appropriate TI depends on the tissue via the formula:
in other words, one should typically use a TI of around 70% of the T1 value. In the case of CSF suppression, one aims for T1-weighted images, which prioritize the signal of fat over that of water. Therefore, if the long TI (inversion time) is adjusted to a zero crossing point for water (none of its signal is visible), the signal of the CSF is theoretically being "erased," from the derived image.[2]
Clinical applicationsedit
The FLAIR sequence analysis has been especially useful in the evaluation and study of CNS disorders, involving:[2]
fluid, attenuated, inversion, recovery, flair, sequence, with, inversion, recovery, null, fluids, example, used, brain, imaging, suppress, cerebrospinal, fluid, effects, image, bring, periventricular, hyperintense, lesions, such, multiple, sclerosis, plaques, . Fluid attenuated inversion recovery FLAIR is an MRI sequence with an inversion recovery set to null fluids For example it can be used in brain imaging to suppress cerebrospinal fluid CSF effects on the image so as to bring out the periventricular hyperintense lesions such as multiple sclerosis MS plaques 1 It was invented by Graeme Bydder citation needed FLAIR can be used with both three dimensional imaging 3D FLAIR or two dimensional imaging 2D FLAIR Postcontrast FLAIR of a case of meningitis It shows enhancement of meninges at the tentorium and in the parietal region with evidence of dilated ventricles Contents 1 Technique 2 Clinical applications 3 See also 4 References 5 Further readingTechnique editBy carefully choosing the inversion time TI the signal from any particular tissue can be nulled The appropriate TI depends on the tissue via the formula TI ln 2 T 1 displaystyle textrm TI ln 2 cdot T 1 nbsp in other words one should typically use a TI of around 70 of the T1 value In the case of CSF suppression one aims for T1 weighted images which prioritize the signal of fat over that of water Therefore if the long TI inversion time is adjusted to a zero crossing point for water none of its signal is visible the signal of the CSF is theoretically being erased from the derived image 2 Clinical applications editThe FLAIR sequence analysis has been especially useful in the evaluation and study of CNS disorders involving 2 Lacunar infarction Multiple sclerosis MS plaques Subarachnoid haemorrhage Head trauma Meningitis and other leptomeningeal diseases Post contrast FLAIR images have been added to diagnosis protocol for accurate medical assessment 2 nbsp Axial fluid attenuated inversion recovery MRI image demonstrating tumor related infiltration involving lenticular nuclei Arrow nbsp Axial fluid attenuated inversion recovery MRI image demonstrating tumor related infiltration involving both temporal lobes Short arrow and the substantia nigra Long arrow See also editRelaxation NMR References edit Bakshi R Ariyaratana S Benedict RH Jacobs L May 2001 Fluid attenuated inversion recovery magnetic resonance imaging detects cortical and juxtacortical multiple sclerosis lesions Archives of Neurology 58 5 742 8 doi 10 1001 archneur 58 5 742 PMID 11346369 a b c Fluid attenuation inversion recovery Radiology Reference Article Radiopaedia org radiopaedia org Retrieved 2015 12 03 Further reading editMcRobbie DW Moore EA Graves MJ Prince MR April 2017 MRI from Picture to Proton Cambridge University Press pp 40 42 Hashemi RH Bradley Jr WG Lisanti CJ eds MRI The Basics 2nd ed Philadelphia p 272 nbsp This article about magnetic resonance imaging is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Fluid attenuated inversion recovery amp oldid 1221890647, wikipedia, wiki, book, books, library,
